On the Tibetan Plateau, there are wild yaks with blood cells thinner than those of horses’ by half, enabling the endangered yaks to survive at 40 below zero and in the lowest oxygen levels of the mountaintops. But climate change is causing the snow patterns here to shift, and with the snows, the entire ecosystem. Food and water are vaporizing in this warming environment, and these beasts of ice and thin air are extraordinarily ill-equipped for the change.

Berger’s quest to understand these creatures’ struggles takes him to some of the most remote corners and peaks of the globe: across Arctic tundra and the frozen Chukchi Sea to study muskoxen, into the Bhutanese Himalayas to follow the rarely sighted takin, and through the Gobi Desert to track the proboscis-swinging saiga.

Known as much for his rigorous, scientific methods of developing solutions to conservation challenges as for his penchant for donning moose and polar bear costumes to understand the mindsets of his subjects more closely, Berger is a guide par excellence.

He is a scientist and storyteller who has made his life working with desert nomads, in zones that typically require Sherpas and oxygen canisters. Recounting animals as charismatic as their landscapes are extreme, Berger’s unforgettable tale carries us with humor and expertise to the ends of the earth and back. But as his adventures show, the more adapted a species has become to its particular ecological niche, the more devastating climate change can be.

Life at the extremes is more challenging than ever, and the need for action, for solutions, has never been greater.